                (a) Field of the Invention        
The present invention relates to an optical recording medium protection cassette, and in particular, to a durable protection cassette with a switch member to indicate protection status of the recording medium.
(b) Description of the Prior Art
Optical principle is commonly employed in storing or recording data in various media, such as Compact Disc (CD), Video Compact Disc (VCD), Digital Versatile Disc (DVD). There are plenty of advantages by employing such optical data recording medium (hereinafter referred as optical recording medium), such as lightweight, thin, short and small, portable, storage time being long, and capable of storing large quantity of data.
One way of performing read/write of an optical recording medium is to install the optical recording medium into a protection cassette and then deliver the cassette to an optical recording medium read/write machine to access the data stored in the optical recording medium. This way of data-accessing, like a floppy disk, is advantageous in that: (1) the surface of the optical recording medium is not subject to scratching; (2) write protection can be set or not on the protection cassette. If write protection of the protection cassette is set, “write-in” to the optical recording medium is not allowed. Thus, loss of important data as a result of accidental “write-in” can be avoided.
FIG. 5 is a schematic view of a conventional optical recording medium protection cassette, which comprises a housing 21 having a first opening 221 at a first lateral side thereof for retaining an optical recording medium, and a third opening 223 being formed at a second lateral side which is perpendicular to the first lateral side; a clasping member 24 being engaged with the first opening 221 of the housing 21 to restrict the optical recording medium within the housing 21; and two second openings 222.
The clasping member 24 is provided with a V-shaped portion 26 and a switch member 27. One end of the switch member 27 is integrally connected at the clasping member 24, the other end is provided with a protruding portion 271. FIGS. 6(a) and 6(b) are partial enlarged views of the clasping member 24, the V-shaped portion 26 and the switch member 27. Referring to FIGS. 6(a) and 6(b), the straight line distance from the connection of the switch member 27 and the clasping member 24 to the apex of the positioning/protruding portion 271 is longer than the straight line distance from the connection of the switch member 27 and the clasping member 24 to the apex of the V-shaped portion 26. Therefore, the position of the apex of the positioning/protruding portion 271, as shown in FIG. 6(a), is at the upper side of the V-shaped portion 26. Alternatively, as shown in FIG. 6(b), the position of the apex of the positioning/protruding portion 271 is at the lower side of the V-shaped portion 26. When the positioning/protruding portion 271 is switched, a substantially elastic deformation occurs as the switch member 27 is substantially L-shaped, such that the positioning/protruding portion 271 can pass through the apex of the V-shaped portion 26. Therefore, the positioning/protruding portion 271 switches at the two states as shown in FIGS. 6(a) and 6(b). Consequently, the write protection status of the optical recording medium in the optical recording medium protection cassette can be represented by switching the position of the positioning/protruding portion 271 of the switch member 27.
The position of the second opening 222 on the housing 21 corresponds to the positioning/protruding portion 271. Therefore, when the clasping member 24 is engaged with the housing 21, the positioning/protruding portion 271 can be switched.
A clip member 28 is formed at the clasping member 24, which has a protruding portion 281 for engaging a third opening 223 on a lateral side of the housing 21, so as to secure the clasping member 24 within the housing 21. FIGS. 7(a) and 7(b) are partial enlarged views of the clip member 28 of the clasping member 24. Referring to FIGS. 7(a) and 7(b), if the clasping member 24 is to be withdrawn, the protruding portion 281 must be pushed away from the third opening 223 via the outside of the housing 21, and then the protruding portion 281 must be pushed down slightly so as to withdraw the clasping member 24 from the housing 21. In this way, the optical recording medium of the optical recording protection cassette can be withdrawn.
The connection between the switch member 27 and clasping member 24 is apt to split as a result of bending while switching the switch member 27. Since the switch member 27 and the clasping member 24 are formed integrally, and the switch member 27 at the write protection status and at non-write protection status are located at different positions, the connection of the switch member 27 and the clasping member 24 must be narrow to facilitate bending. As a result, the connection is apt to split after several times of bending and the function to set write protection for the optical recording medium in the optical recording medium protection cassette will be lost.
Another drawback of the prior art is that the sharp angle at the apex of the positioning/protruding portion 271 and the apex of the V-shaped portion 26 will become blunt after switching for several times. If the bluntness is severe, the distance from the connection of the switch member 27 and the clasping member 24 to the apex of the positioning/protruding portion 271 may approximate to the distance from the connection of the switch member 27 and the clasping member 24 to the apex of the V-shaped portion 26. This causes poor positioning function between the positioning/protruding portion 271 and the V-shaped portion 26. Therefore, the function of write protection indication is lost.
Still another drawback of the prior art is that the operation of the clip member 28 is not easy. It is thus not easy to withdraw the clasping member 24. Specifically, when the clasping member 24 is to be withdrawn, the protruding portion 281 of the clip member 28 must be pushed inward and the clasping member 24 must be pushed slightly sidewards. Otherwise, the protruding portion 281 will re-bounce back to the third opening 223. However, in accordance with the prior art, it is not easy to push the clasping member sidewards. Therefore, the optical recording medium is not easily withdrawn from the optical recording medium protection cassette, and not easily loaded into the optical recording medium protection cassette.